[include] Made PMC_IS_NULL into a macro when used in Parrot's core.  The function calling overhead is statistically significant (around 3.5% on the Rakudo benchmark).
[include] Made PMC_IS_NULL into a macro when used in Parrot's core.  The
function calling overhead is statistically significant (around 3.5% on the
Rakudo benchmark).

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@29991 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot